Drainage tile



Patented June 20, 1939 UNITED STATES DRAINAGE TILE Frank S. Wuelker, St.Louis, Mo., assignor to. Laclede-Christy Clay Products Company, acorporation of Missouri Application August 23, 1938, Serial No. 226,282

1 Claim.

This invention relates to drainage tiles, and consists in a tile forunder-drain filters that is efficient, durable, and cheap tomanufacture.

In the accompanying drawing Fig. I is a view in perspective of the tileof the invention, and

Fig. II is a view of it in plan from beneath.

It has long been the practice of engineers, in preparing plans andspecifications on sewagetreatment plants of the trickling filter type,to

specify that split sewer pipe be placed in rows about two feet apart,split side down, on the floor of the tank; and upon the so-placed pipebroken stone is heaped and spread within the tank, to a depth of aboutseven feet. In the operation of the plant liquid sewage is spread uponthe upper surface of the bed of stone, and filterin action ensues. Thefioor of the tank slopes to a central well and the rows of split pipethat lie upon the floor of the tank afford channels, to aid in causingthe eflluent to pass to the well. They afford also access of air, foraeration of the bed of stone. V

A split pipe, with no further refinement of shape, is ill-suited to suchservice; because, in the prolonged operation of the filter, a jellycollects at the line where the split pipe rests on the floor of thetank; and the so collecting jelly hinders the escape of efliuent andhinders also the ingress of air. To overcome the difficulty, the

30 proposal has been made, to notch the edges of the lengths of splitpipe; but it has been found that by the notching the load-bearingstrength of the split pipe has been seriously impaired. It has becomethe practice, therefore, to provide 35 drainage tile members for thisuse of more elaborate structure, and of more costly production.

I have found that I may retain the simpler structure of a split pipewith notched edges by so arranging the notches that they succeed one an-40 other in staggered arrangement on opposite edges throughout thelength of the pipe; that at no point does a notch on one edge comeopposite to a notch on the other edge; and that in the longitudinalsuccession of opposite notches an in- 45 tegral and unnotched portion ofthe pipe shall intervene between each notch and the next succeeding (andopposite) notch. Referring to Fig. II of the drawing, the length ofsplit pipe I is, along its two edges notched with notches 2, 3, 4.

50 5, etc. The staggered arrangement is manifest; while between notch 2on one edge and notch 3 on the other, a length of unnotched pipe body a,marked off by dotted lines, intervenes.

Consider now the structure of the split pipe laid split side down uponthe floor of the filter tank. It becomes a barrel vault, carrying theload of the filter bed. It is characteristic of the tile of my inventionthat, throughout all of its 5 extent, and on every plane ofcross-section, the crown of the vault, on one side at least, findsdirect support on the floor of the tank. Throughout the intervals a suchdirect support is afforded on both sides; and elsewhere, the support onone 10 side being direct, it is on the other side forked: the supportfor such portion of the vault is Y- shaped. That is to say, consideringthe portion b, its support on one side is direct, as by the stem of a Yat c; and on the opposite side it .is forked 15 as through the branchesof a Y, at d and e. Spe+ cifically, the split pipe of my invention mayhave a cylindrical and uniform body 36 inches long and 8 inches indiameter (or, perhaps, 6 or 10 or 12 inches in diameter). At one end itmay be 20 provided with a bell for bell-and-spigot union with anotherlike unit, or it may be plain and unelaborated. Along each edge of theuniform body four slots are formed, each 3 inches long and 2 inchesdeep. The centre to centre spacing is 8 inches. The slots are staggeredin their succession. along the two edges, and the centre to centrespacing from a slot on an edge to the next succeeding slot on the otheredge is (measured in the length of the pipe) 4 inches. The intervals a,then, of continuous and unnotched body, are 1 inch in longitudinalextent. I give these figures by way of illustration, merely.

With slots so arranged and proportioned the load is evenly distributedand the structure is strong to sustain the load. The desired facility offiow of efliuent is afforded and the desired aeration.

I claim as my invention:

A drainage tile for a filter consisting of a split pipe with notchededges, the notches upon the opposite edges being arranged in staggeredsuccession, and the length of each notch being less than the centre tocentre interval between a notch on one edge and the next succeedingnotch on the other, whereby portions of the vault afforded by the tilewhen in service extend between the notches, in continuity from thesupporting floor on one side to the supporting floor on the other.

FRANK S. WUELKER.

